//////////////////////////////////////////////////////////////////////////////////////////////
        // Creates a new GraphicsNode that contains our graphic symbol
        //
        //////////////////////////////////////////////////////////////////////////////////////////////
        GraphicsNode DrawSymbol(
            UnitVector normal,
            Point center,
            double radius)
        {
            Circle circle = _Tg.CreateCircle(center, normal, radius);

            double[] up    = new double[] { center.X, center.Y + radius, 0 };
            double[] down  = new double[] { center.X, center.Y - radius, 0 };
            double[] right = new double[] { center.X + radius, center.Y, 0 };
            double[] left  = new double[] { center.X - radius, center.Y, 0 };

            GraphicsNode node = _clientGraphicsMng.CreateNewGraphicsNode();

            node.Selectable = true;

            CurveGraphics curve    = _clientGraphicsMng.DrawCurve(circle, node);
            LineGraphics  lineVert = _clientGraphicsMng.DrawLine(up, down, node);
            LineGraphics  lineHorz = _clientGraphicsMng.DrawLine(left, right, node);

            return(node);
        }